Theodore Ts'o | fe263da | 2008-02-16 14:14:24 -0500 | [diff] [blame] | 1 | /* |
| 2 | * ismounted.c --- Check to see if the filesystem was mounted |
| 3 | * |
| 4 | * Copyright (C) 1995,1996,1997,1998,1999,2000,2008 Theodore Ts'o. |
| 5 | * |
| 6 | * %Begin-Header% |
| 7 | * This file may be redistributed under the terms of the GNU Public |
| 8 | * License. |
| 9 | * %End-Header% |
| 10 | */ |
| 11 | |
| 12 | #include <stdio.h> |
| 13 | #if HAVE_UNISTD_H |
| 14 | #include <unistd.h> |
| 15 | #endif |
| 16 | #ifdef HAVE_STDLIB_H |
| 17 | #include <stdlib.h> |
| 18 | #endif |
| 19 | #if HAVE_ERRNO_H |
| 20 | #include <errno.h> |
| 21 | #endif |
| 22 | #include <fcntl.h> |
| 23 | #ifdef HAVE_LINUX_FD_H |
| 24 | #include <linux/fd.h> |
| 25 | #endif |
| 26 | #ifdef HAVE_MNTENT_H |
| 27 | #include <mntent.h> |
| 28 | #endif |
| 29 | #include <string.h> |
| 30 | #include <sys/stat.h> |
Theodore Ts'o | 2d328bb | 2008-03-17 23:17:13 -0400 | [diff] [blame] | 31 | #include <ctype.h> |
| 32 | |
| 33 | #include "fsck.h" |
Theodore Ts'o | fe263da | 2008-02-16 14:14:24 -0500 | [diff] [blame] | 34 | |
| 35 | /* |
| 36 | * ext2fs_check_if_mounted flags |
| 37 | */ |
| 38 | #define MF_MOUNTED 1 |
| 39 | |
| 40 | #include "et/com_err.h" |
| 41 | |
JP Abgrall | e0ed740 | 2014-03-19 19:08:39 -0700 | [diff] [blame] | 42 | #ifdef HAVE_SETMNTENT |
Theodore Ts'o | fe263da | 2008-02-16 14:14:24 -0500 | [diff] [blame] | 43 | static char *skip_over_blank(char *cp) |
| 44 | { |
| 45 | while (*cp && isspace(*cp)) |
| 46 | cp++; |
| 47 | return cp; |
| 48 | } |
| 49 | |
| 50 | static char *skip_over_word(char *cp) |
| 51 | { |
| 52 | while (*cp && !isspace(*cp)) |
| 53 | cp++; |
| 54 | return cp; |
| 55 | } |
| 56 | |
| 57 | static char *parse_word(char **buf) |
| 58 | { |
| 59 | char *word, *next; |
| 60 | |
| 61 | word = *buf; |
| 62 | if (*word == 0) |
| 63 | return 0; |
| 64 | |
| 65 | word = skip_over_blank(word); |
| 66 | next = skip_over_word(word); |
| 67 | if (*next) |
| 68 | *next++ = 0; |
| 69 | *buf = next; |
| 70 | return word; |
| 71 | } |
JP Abgrall | e0ed740 | 2014-03-19 19:08:39 -0700 | [diff] [blame] | 72 | #endif |
Theodore Ts'o | fe263da | 2008-02-16 14:14:24 -0500 | [diff] [blame] | 73 | |
| 74 | /* |
| 75 | * Helper function which checks a file in /etc/mtab format to see if a |
| 76 | * filesystem is mounted. Returns an error if the file doesn't exist |
| 77 | * or can't be opened. |
| 78 | */ |
| 79 | static errcode_t check_mntent_file(const char *mtab_file, const char *file, |
| 80 | int *mount_flags) |
| 81 | { |
JP Abgrall | e0ed740 | 2014-03-19 19:08:39 -0700 | [diff] [blame] | 82 | #ifdef HAVE_SETMNTENT |
Theodore Ts'o | fe263da | 2008-02-16 14:14:24 -0500 | [diff] [blame] | 83 | struct stat st_buf; |
| 84 | errcode_t retval = 0; |
| 85 | dev_t file_dev=0, file_rdev=0; |
| 86 | ino_t file_ino=0; |
| 87 | FILE *f; |
| 88 | char buf[1024], *device = 0, *mnt_dir = 0, *cp; |
Theodore Ts'o | fe263da | 2008-02-16 14:14:24 -0500 | [diff] [blame] | 89 | |
| 90 | *mount_flags = 0; |
Theodore Ts'o | fe263da | 2008-02-16 14:14:24 -0500 | [diff] [blame] | 91 | if ((f = setmntent (mtab_file, "r")) == NULL) |
| 92 | return errno; |
| 93 | if (stat(file, &st_buf) == 0) { |
| 94 | if (S_ISBLK(st_buf.st_mode)) { |
| 95 | #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ |
| 96 | file_rdev = st_buf.st_rdev; |
| 97 | #endif /* __GNU__ */ |
| 98 | } else { |
| 99 | file_dev = st_buf.st_dev; |
| 100 | file_ino = st_buf.st_ino; |
| 101 | } |
| 102 | } |
| 103 | while (1) { |
| 104 | if (!fgets(buf, sizeof(buf), f)) { |
| 105 | device = mnt_dir = 0; |
| 106 | break; |
| 107 | } |
| 108 | buf[sizeof(buf)-1] = 0; |
| 109 | |
| 110 | cp = buf; |
| 111 | device = parse_word(&cp); |
| 112 | if (!device || *device == '#') |
| 113 | return 0; /* Ignore blank lines and comments */ |
| 114 | mnt_dir = parse_word(&cp); |
| 115 | |
| 116 | if (device[0] != '/') |
| 117 | continue; |
| 118 | |
| 119 | if (strcmp(file, device) == 0) |
| 120 | break; |
| 121 | if (stat(device, &st_buf) == 0) { |
| 122 | if (S_ISBLK(st_buf.st_mode)) { |
| 123 | #ifndef __GNU__ |
| 124 | if (file_rdev && (file_rdev == st_buf.st_rdev)) |
| 125 | break; |
| 126 | #endif /* __GNU__ */ |
| 127 | } else { |
| 128 | if (file_dev && ((file_dev == st_buf.st_dev) && |
| 129 | (file_ino == st_buf.st_ino))) |
| 130 | break; |
| 131 | } |
| 132 | } |
| 133 | } |
| 134 | |
| 135 | if (mnt_dir == 0) { |
| 136 | #ifndef __GNU__ /* The GNU hurd is broken with respect to stat devices */ |
| 137 | /* |
| 138 | * Do an extra check to see if this is the root device. We |
| 139 | * can't trust /etc/mtab, and /proc/mounts will only list |
| 140 | * /dev/root for the root filesystem. Argh. Instead we |
| 141 | * check if the given device has the same major/minor number |
| 142 | * as the device that the root directory is on. |
| 143 | */ |
| 144 | if (file_rdev && (stat("/", &st_buf) == 0) && |
| 145 | (st_buf.st_dev == file_rdev)) |
| 146 | *mount_flags = MF_MOUNTED; |
| 147 | #endif /* __GNU__ */ |
| 148 | goto errout; |
| 149 | } |
| 150 | #ifndef __GNU__ /* The GNU hurd is deficient; what else is new? */ |
| 151 | /* Validate the entry in case /etc/mtab is out of date */ |
| 152 | /* |
| 153 | * We need to be paranoid, because some broken distributions |
| 154 | * (read: Slackware) don't initialize /etc/mtab before checking |
| 155 | * all of the non-root filesystems on the disk. |
| 156 | */ |
| 157 | if (stat(mnt_dir, &st_buf) < 0) { |
| 158 | retval = errno; |
| 159 | if (retval == ENOENT) { |
| 160 | #ifdef DEBUG |
| 161 | printf("Bogus entry in %s! (%s does not exist)\n", |
| 162 | mtab_file, mnt_dir); |
| 163 | #endif /* DEBUG */ |
| 164 | retval = 0; |
| 165 | } |
| 166 | goto errout; |
| 167 | } |
| 168 | if (file_rdev && (st_buf.st_dev != file_rdev)) { |
| 169 | #ifdef DEBUG |
| 170 | printf("Bogus entry in %s! (%s not mounted on %s)\n", |
| 171 | mtab_file, file, mnt_dir); |
| 172 | #endif /* DEBUG */ |
| 173 | goto errout; |
| 174 | } |
| 175 | #endif /* __GNU__ */ |
| 176 | *mount_flags = MF_MOUNTED; |
| 177 | |
| 178 | retval = 0; |
| 179 | errout: |
| 180 | endmntent (f); |
| 181 | return retval; |
JP Abgrall | e0ed740 | 2014-03-19 19:08:39 -0700 | [diff] [blame] | 182 | #else /* !HAVE_SETMNTENT */ |
Theodore Ts'o | 2a6b604 | 2008-06-07 19:01:46 -0400 | [diff] [blame] | 183 | return 0; |
| 184 | #endif /* HAVE_MNTENT_H */ |
Theodore Ts'o | fe263da | 2008-02-16 14:14:24 -0500 | [diff] [blame] | 185 | } |
| 186 | |
| 187 | int is_mounted(const char *file) |
| 188 | { |
| 189 | errcode_t retval; |
| 190 | int mount_flags = 0; |
| 191 | |
| 192 | #ifdef __linux__ |
| 193 | retval = check_mntent_file("/proc/mounts", file, &mount_flags); |
| 194 | if (retval) |
| 195 | return 0; |
| 196 | if (mount_flags) |
| 197 | return 1; |
| 198 | #endif /* __linux__ */ |
| 199 | retval = check_mntent_file("/etc/mtab", file, &mount_flags); |
| 200 | if (retval) |
| 201 | return 0; |
| 202 | return (mount_flags); |
| 203 | } |
| 204 | |
| 205 | #ifdef DEBUG |
| 206 | int main(int argc, char **argv) |
| 207 | { |
| 208 | if (argc < 2) { |
| 209 | fprintf(stderr, "Usage: %s device\n", argv[0]); |
| 210 | exit(1); |
| 211 | } |
| 212 | |
| 213 | if (is_mounted(argv[1])) |
| 214 | printf("\t%s is mounted.\n", argv[1]); |
| 215 | exit(0); |
| 216 | } |
| 217 | #endif /* DEBUG */ |